The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A079537

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a(n) = phi(2*n+1)*d(2*n+1) - sigma(2*n+1).
(history; published version)

#8 by Charles R Greathouse IV at Thu Sep 08 08:45:08 EDT 2022

PROG

(MAGMAMagma) [EulerPhi(2*n+1)*DivisorSigma(0, 2*n+1) - DivisorSigma(1, 2*n+1): n in [0..80]]; // G. C. Greubel, Jan 15 2019

Discussion

Thu Sep 08

08:45

OEIS Server: https://oeis.org/edit/global/2944

#7 by Susanna Cuyler at Tue Jan 15 18:47:01 EST 2019

STATUS

reviewed

approved

#6 by Vaclav Kotesovec at Tue Jan 15 13:17:30 EST 2019

STATUS

proposed

reviewed

#5 by G. C. Greubel at Tue Jan 15 13:08:51 EST 2019

STATUS

editing

proposed

#4 by G. C. Greubel at Tue Jan 15 13:08:23 EST 2019

NAME

a(n) = phi(2*n+1)*d(2*n+1) - sigma(2*n+1).

LINKS

G. C. Greubel, <a href="/A079537/b079537.txt">Table of n, a(n) for n = 0..10000</a>

MATHEMATICA

Table[EulerPhi[2*n+1]*DivisorSigma[0, 2*n+1] - DivisorSigma[1, 2*n+1], {n, 0, 80}] (* G. C. Greubel, Jan 15 2019 *)

PROG

(PARI) vector(80, n, n--; eulerphi(2*n+1)*sigma(2*n+1, 0) - sigma(2*n+1, 1)) \\ G. C. Greubel, Jan 15 2019

(MAGMA) [EulerPhi(2*n+1)*DivisorSigma(0, 2*n+1) - DivisorSigma(1, 2*n+1): n in [0..80]]; // G. C. Greubel, Jan 15 2019

(Sage) [euler_phi(2*n+1)*sigma(2*n+1, 0) - sigma(2*n+1, 1) for n in (0..80)] # G. C. Greubel, Jan 15 2019

STATUS

approved

editing

#3 by Russ Cox at Fri Mar 30 16:49:38 EDT 2012

AUTHOR

_N. J. A. Sloane (njas(AT)research.att.com), _, Jan 23 2003

Discussion

Fri Mar 30

16:49

OEIS Server: https://oeis.org/edit/global/110

#2 by N. J. A. Sloane at Fri Feb 27 03:00:00 EST 2009

KEYWORD

nonn,new

nonn

AUTHOR

N. J. A. Sloane (njas, (AT)research.att.com), Jan 23 2003

#1 by N. J. A. Sloane at Fri May 16 03:00:00 EDT 2003

NAME

phi(2*n+1)*d(2*n+1) - sigma(2*n+1).

DATA

0, 0, 2, 4, 5, 8, 10, 8, 14, 16, 16, 20, 29, 32, 26, 28, 32, 48, 34, 40, 38, 40, 66, 44, 69, 56, 50, 88, 64, 56, 58, 112, 108, 64, 80, 68, 70, 116, 144, 76, 149, 80, 148, 104, 86, 176, 112, 168, 94, 204, 98, 100, 192, 104, 106, 136, 110, 208, 250, 240, 197, 152, 244, 124, 160

OFFSET

0,3

COMMENTS

It is known that a(n) >= 0.

REFERENCES

D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 10.

CROSSREFS

Cf. A000010, A000005, A000203, A079536.

KEYWORD

nonn

AUTHOR

njas, Jan 23 2003

STATUS

approved